I have a Validation > Model > General > “Beam centre-line is outside slab plane / boundary” warning. Why do I get this and how do I resolve it?

Not version-specific

Tekla Structural Designer

Environment

Not environment-specific

Question

I have a Validation > Model > General > “Beam centre-line is outside slab plane / boundary” warning. Why do I get this and how do I resolve it?

Answer

A Beam centre-line is outside slab plane / boundary validation warning occurs if you have adjusted the alignment of the beam such that the centre-line of the beam is now located outside the slab boundary.

If we hover over the Beam centre-line is outside slab plane / boundary validation warning or an item listed within the branch, a tooltip is displayed “Beam will not receive slab loads, consider changing alignment”. Hence, if the warning is ignored the slab edge is unsupported and hence the load path is perhaps not as intended.

We can double click the “Beam centre-line is outside slab plane / boundary” warning or an individual item listed under the branch. If the items exist in the active view they will be highlighted. If they do not exist in the active view then Tekla Structural Designer will automatically switch to the 3D Structure view regime and highlight the item. Alternatively, you can right click and choose Highlight Items from the context menu. The selected item(s) are also displayed in the Properties window for review and editing. We have highlighted the Alignment section in the Properties window.

Reviewing the above screenshot, the columns and beams along grid line 1 appear to align along the outer edge - so what is the issue? If we zoom in and investigate further, we should be able to see that the slab boundary runs along the gridline and the beam centre-line (it’s analysis wire) is located outside the slab edge which runs along this gridline. This can be more clearly seen if you review the Solver view regime.

Hence, as advised in the tooltip, any load applied to the slab will not decompose to the beam since it is not supporting the slab. This may not be as intended.

It would be useful to read the Analysis models and options section in the Tekla Structural Designer product guides at this point for you to gain an understanding of how the analysis model is constructed and an appreciation of the alignment wire (insertion line), analysis wire (centre-line of beam) and rigid offsets.

The Alignment section of the Properties window allows you to adjust the location of the physical element with respect to the alignment wire (insertion line).

To resolve the issue, adjust the Alignment section of the Properties window to ensure that the beam centre-line sits either on/or within the slab boundary

Solution 1

Beam (and column alignment), is edited so that the alignment wire (insertion line) is located at the slab boundary. The effect is that the centre line of the beam (beam analysis wire) is 250 mm /2 = 125mm within the slab. This would be the typical method for modelling concrete beams and slabs to ensure a flush outer face.

Solution 2

Beam (and column alignment), edited so that the alignment wire (insertion line) is located such that the centre-line of the beam aligns with the slab boundary.

After making one of the amendments above. No validation warnings of type Beam centre-line is outside slab plane / boundary are reported.